Prevalence and Antimicrobial Susceptibility of Gram Negative Bacteria Isolated From Urinary Tract Infections

Abid Sarwar¹, Sohail Aslam¹, Muhammad Asif Habeeb^1*

*Corresponding author:asif.habeeb@imbb.uol.edu.pk

ARTICLE CITATION: Sarwar A, Aslam S, Habeeb MA (2013).Prevalence and Antimicrobial Susceptibility of Gram Negative Bacteria Isolated From Urinary Tract Infections.J. Inf. Mol. Biol. 1 (2): 35 – 37.
Received: 2013-03-05, Revised: 2013-04-02, Accepted: 2013-04-03
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ABSTRACT

Prevalence and antimicrobial resistance pattern of pathogens involved in urinary tract infections (UTI)could be used to monitor therapeutic measures and subsequent change in antibiotics administration. Urine samples (n = 100) were collected aseptically from patients suspected of UTI originating from different hospitals (n = 4) of Lahore City and subjected to conventional microbiological procedures for isolation and identification of bacteria, and antimicrobial susceptibility.Of the total examined, 71 samples showed positivity to bacterial growth.Escherichia coli (50%) was the most prevalent bacteria found in urine samples followed by Pseudomonas aeruginosa(20%), Klebsiella pneumonia (17%) andProteus mirabilis(13%).All isolates showed high resistance to vancomycin and ampicillin whereas efficacy of amikacin against all the pathogens was incredibly excellent.

Urinary tract infections (UTI) represent serious threats to human health all around the world affecting millions of people each year(Reed and Kemmerly, 2009). These are the most common nosocomial as well as community acquired infections,resulting in high morbidity and increased economic loss in terms of treatment (Ojo and Anibijuwon, 2010). UTIs are widespread in both males and females; nevertheless, females are more susceptible than males (Mohsin and Siddiqui, 2010; McGregor et al., 2013). In early childhood, persistent urinary tract infections may usually emerge and 1 to 8% of children may experience UTI at least once between the age of 1 and 11 years (Kõljalg et al., 2009).

The causative agents of UTI may include bacteria, virus and fungi(Ojo and Anibijuwon, 2010). Of these, gram negative bacilli are the most prevalent uropathogens including Escherichia coli, Klebsiella pneumoniae,Pseudomonas aeruginosa and Proteus mirabilisthat resultin bacteremia and hospital acquired infections (Tabibian et al., 2008; Kolawole et al., 2009).

Because of recommended empirical antimicrobial regimen, antimicrobial resistance is one of the most important and alarming risk factors in urinary tract infections(Karlowsky et al., 2002).A little is known of the causative agents and antimicrobial susceptibility of pathogens associated with UTIs in nosocomial and community acquired infections originating from Lahore City. The study, therefore, has been conducted to determine the prevalence and antimicrobial susceptibility of pathogens involved in UTIs originating from different hospitals of Lahore City.

From four tertiary care hospitals in Lahore named Jinnah Hospital (JH), Ittefaq Hospital (IH), ShaikhZayed Hospital (SZH) and Lahore General Hospital (LGH), patients (n = 100) suspected of urinary tract infections were included during the period from March to June, 2012. Urine samples were collected aseptically from male (n = 50) and female (n = 50) patients andtransferred to the Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan at refrigerated temperature. The Proportions of the samples collected from each hospital is given in Table 1.

On basis of colony morphology,bacterial pathogens were isolated from urine samples onCysteine Lactose Electrolyte Deficient (CLED) agar (Merck, Darmstadt, Germany) and these isolated colonies were further purified on MacConkey agar (Merck, Darmstadt, Germany). Bacteria having different colony morphology from each other were further identified by different biochemical tests and results were interpreted using the guidelines of Clinical and Laboratory Standards Institute 2012(CLSI, 2012).

All isolated bacterial pathogens were subjected for susceptibility testing for most commonly used antimicrobial agents in case of urinary tract infections. These includeampicillin (10µg), aztreonam (30µg) (β lactam), cephalexin (30µg) (cephalosporin), vancomycin(30µg) (glycopeptide) and amikacin (30µg) (aminoglycoside). For antibiotic sensitivity test, Disc Diffusion Test was conducted on Muller Hinton Agar (Merck, Darmstadt, Germany) using antibiotics on paper discs (Oxoid, Hampshire, UK); zone of inhibition were measured and results were interpreted according to guidelines of Clinical and Laboratory Standards Institute 2012 (CLSI, 2012).

Data obtained in this study was evaluated statistically using Fisher’s exact test. For proportion comparison between two groups of patients, two tailed p value <0.05 was considered statistically significant.

Out of one hundred urine samples, seventy one samples were found positive for bacterial growth. Among 71 positive samples, 46 (65%) were of female patients and 25 (35%)urine samples were of male patients. On the basis of biochemical testing, four types of bacterial populations were identified; the distribution of these bacterial isolates is shown in Table 2.